Self-regulating furnace.



M. J. & H. B. FARQUHAR. SELF REGULATING FURNACE.

APPLIUATIOH FILED MAY 16, 1904.

Patented June 1, 1909.

2 SHEETS-SHEET 2.

y I INVENTORS Alf/a4.

Wm ATTORNHJ.

llhllTlEll @Tg t FATENT enrich.

MILTON J. FARQUHAR AND HENRY B. FARQTJHAR, OF WILMINGTON, OHIO, ASSIGNORS, BY DIRECT AND MESNE ASSIGNMENTS, TO THE FARQUHAR FURNACE COMPANY, OF WIL MINGTON, OHIO, A (,ORPORAJION OF OHIO.

SE LF-RE GULATII-TG FURNACE Specification of Letters Patent.

Patented June 1, 1909.

Application filed May 16, 1904. Serial No. 208,218.

T all whom it may concern:

Be it known that we, MILTON J. FARQUHAR and HENRY l3. FARQI'HAR, citizens of the United States, residing at Wilmington, in the county of Clinton and State of Ohio, have invented certain new and useful improvements in Self-Regulating Furnaces; and we do hereby declare the following to be full, clear, and exact description of the in ention,

such as will enable others skilled in the art to which it appertains to make and use the salne.

This invention relates to stoves and furnaces, and particularly to devices for controlling the temperature of the fire-box and regulating the combustion of the fuel. i In the accompanying drawings, which are to be taken as a part of this specification, we have represented our invention embodied in shot-air furnace of horizontal type, of simi .lar construction and design to the furnace shown and described in our copending application for patent, filed March 15, 1902, Serial No. 98445; but it will be understood that the invention is not limited to this or any specific embodiment and is capable of incorporation in various styles of stoves and furnaces well as susceptible to modifications in details of construction and arrangement. The following description will therefore be given with reference more articularly to the illustrated furnace, em odying our invention, which will thereafter be defined in the claims. 7

The principal objects of the invention are: to ,obtain better control of the combustion, by means of the draft, both in starting the lire and whenthe furnace is in operation, with a view to promoting combustion, gencrating a maximum amount of heat from the fuel, and utilizing practically all the heat without waste to automatically regulate the draft-openings, so as to maintain a constant temperature, prevent waste and damage through carelessness or accident in attending to the furnace, render the furnace self-regulating, and especially prevent accidental overheating; and to arrange the various doors, openings and regulatingdevices where most effective and convenient to the one managing the furnace.

Figure 1 of the drawings 'is a perspective view of the aforementioned furnace, embodying our invention, with part of the outside casing or air-box broken away. In this View, the ash-door and automatic controlling mechanism at the front are represented in the position assumed when the furnace is at a low temperature. Fig. 2 is a fragmentary perspective view of the furnace-front, showing the ash-door open wide, as when starting the furnace, and held so by engagement of 3. lug on the ash-door with a finger or lug on the check-valve of the lower smoke-box at the front of the furnace. Fig. 3 is a View similar to Fig. 2, showing the automatic governing mechanism, when it has been moved, owing to an increase in temperature of the fire-box, and has released or closed the ash-door, while it has raised the said checkvalve or lid of the lower smoke-box. Fig. 4 is a perspective View of a fragment of the upper furnace front, showing the front of the upper smoke-box broken away and its damper open. Fig. 5 is a central longitudinal vertical section of said furnace. Fig. 6 is a perspective view of the furnce front, looking at the opposite side to that shown in Figs. 1, 2 and 3. In this view the doors and governing devices are in the positions assumed when the furnace is running and at an ordinary temperature. Fig. 7 is a detail'view of the damper in the upper smoke-box.

The numeral 1 denotes the outer casing of the air-box; 2 the ire-box, which is of horizontal tubular form and closed at the rear; 3 the front plate of the lire-box, outside the front Wall of the air-bo ;-4 the fire-door; 5

the ash-door; 6 the check-door or valve of the smoke-box 7, which latter is located at the lower front of the furnace; S the grate; 9 the roar bridge-wall 10 a passage or 1 lue from the fuel-space down behind the bridge-wall, or between it and the hack-plate of the lirebox; 11 a smoke-passage or llue extending from said passage 10 forward along or under the ash-pan to the smoke-box 7, which hitter has an outlet to the smoke-pipe or chimney 12 located preferably below or at the base of the frontcnd of said passage 11', so as to draw off only the coolest lower strata of the products of combustion. It will be observed that the furnace represented is of the indirect draft type; for the smoke and productsof combustlon pass from the fire over the rear bridge-wall, down the back flue or passage 10, and forward through the passage 11 to the smoke-box 7. Air is of course supplied to the fuel fromthe ash-door 5, passing up through the grate and in this type of furnaceprefcrably an air-blast is also admitted from the. rear of the ashant through a ps'sage, in the bridge-wall to theiire-space above the fuel, where it meets the gases at a heat suflicient to ignite the mixture. The construction thus far described is substan tially similar to that shown and described in our aforesaid copending application Serial No. 98445; this particular furnace, to wh ch our 1nvent1on 1S especially adapted, being illustrated for the purpose of setting forth the invention most clearly and satisfactorily.

At the upper part of the fire-box is an upper smoke-box 13, communicating with the smoke-pipe 12. This upper smoke-box is shown as a casing extending across the upper part of thefront-plate 3, from which it projects, and is joined at one end to the smokepipe, the opposite end being closed. However, the smoke-pipe may-be locatedyat slotsor 'openin s'in the lower wall of said smoke-box. T o weight of the damper or plate 14,-when in front of the fulcrums of the ever, will hold it open-as in Figs. A and 5;

. manual when desired and also automatic, by

and, when tilted-foyer to the opposite side of or behind said fulcrums,will carry it against the draft-opening and hold it there. The damper may be operated by the trip-lugs or fingers 16, 17, such operation being both means of the... heat-governing mechanism hereinafter described. This upper smokebox,with the valve-controlled draft-opening, provides a'direct draft to the smoke-pipe at the upper front or part of'the fire-pox, which may e availed of when necessary or desired. The damper is opened when the fire is started, or when the fire is burning low and it is necessary for the furnace to draw hard in order to increase the rate of combustion quickly; and it is closed when the furnace is at high heat or running at its re ular temperature, so that only the indirect is far more economical. The direct damper draft is also opened when the operator 0 ens the fire-door, so as to revent' smoke rom flying out through the re'door.

Coming now to the automatic governingdraft is used, which I mechanism, 20 denotes a lever depending from its fulcrum 21 at one side of the frontplate and held outward or with its lower end. away from the furnace-front by means of av weight 22. This lever, which controls the various dampers or doors automatically, is actuated to swing inward .by the rising temperature of the furnace; .for which purpose we preferably utilize, as in the furnace of our other application Serial No. 98445, the force of expansion of the fire-box when heated against an inclosing frame not ailected by the heat. Said frame as shown consists of a rear cross-piece 23, having pins or projections 24 that bear against the back of the by the heat; and. longitudinal connecting rods 25 and 26 connected to opposite ends of said cross-piece; one of which rods25 is connected to the lever 20 a little below its fulcrum, as at 27 while the other rod 26 is con- ,nected to an adjusting lever 28 having a tooth engaging a graduated locking rack 29, by means of which the lever 28 can be adjusted to extend or shorten the frame so as to cause the expansion of the fire-box to act on the 'frame at different temperatures.

The adjusting lever may be operated by suit-' able connections from .an upper room in the. building if desired. The frame-work is set outside the air-box, so as to be practically unaffected by the temperature of the furnace. It may surround the air-box as described, or may occupy one side only, the adjusting device being suitably located to correspond.

It is understood that when the heat of thefire-box causes it to expand against the rear cross-piece 23, the rod 25 draws the lever 20.

inward with suflic'ient force to overcome the Wei ht.

T18 lever 20, in its inward and outward fire-box to receive its thrust when expanded movements, controls the ash-door 5, the

check-door or valve 6 in the lower smokebox, and the damper or valve 14 in the upper smokebox; for which purpose means substantially as follows or other suitable devices are rovided.

or wit 1 its upper hinge behind its lower one.

T 1e ash-door 5 is in this instance self- I olosin by arranging its hinges eccentrically A finger 30 projecting from the door engages the lever 20, holding the door partly open while the lever remamsoutward but jas the lever is drawn inward the door follows it and is allowed to gradually move inward or close. Other equivalent arrangements may of course be adopted, such as hinging the door at the top instead of at the side as shown; or the door may be so connected with the lever as to be positively moved thereby bothin opening and closing. Thus, as the tempera-. ture of the furnace is raised by the combustion of the fuel, the door is gradually moved inward to. a position needed to maintain the desired temperature, according to the adjusttemperature, during the furnace, is thus autoy p oy the drawing hack e rod which is conol' e intainerl .215 ct.

low 21' smoko-box,

*(l at its upper v V has a linger and the lows-r laptod to be onwhich in end, tli orproje I 3i,

part of the le gaged th shy when th lever drawn still iarthcr inward, or after sair lover has a-- i owed the ash'door to close. The {-ll'oct of such. engagement is to raise or open slightly the check-door or valve 6, thereby admitting a draft directly to the smoke-pipe or chimney, to relieve or check the draft thereto rorn the fire-box and consequently lzfwcr combustion. Thus should the temperature of the fire-box rise higher than desired, notwithstanding the closing oi the ash-door, in moderate weather or when the fire is allowed to burn high by thoughtlessness in leaving open the ash-door, the check-door will opened and cause a reduction of tern iera ture.

The n-door can be held. wide open, when g desired, by means of a. hug 32 thereon adapted when the door so opened to engage a linger 33 projecting, from the choclwloor so as to permit the lug to move outwardly past it but abut it when moved back. in starting the tire, it desirable thus to open the ashalocr all the wav; but should tho atl tcndantthrough accident or l'orgctlulnoss no 1 away wit-innit closing the ash-door, thcauim matic gOJt ning dovicr will take (it 'o of this; for as soon as ti temperature l' tin furnace ris suliicicntl to draw tho lever 20 inward iiost the linger 5-31 on tho chockl door, said check-t our will be raised, releasing 1 the asl1-door and allowing it to close; while at the same than the dral't admitted the 1 lower snooi. box ilil 'libl the combustion in ths tire-box and. lo" the temperature. l temperature 5 l l After-this action occurs, as the iyberelaxcd 1 amount non ot' this .i tiil to ennnoy a. sol

loun 16 of the valvecarrying lever 15, another arm of which pro ects behind the lever 20,

, action or lug on the arm 0 of tri-arm lever 34 will cause the upper arm athcreol to engage the trip or tail-piece l6 and thus tilt the lever 15 to close the drattvalvo; which however can again be opened by hearing down =with the hand against one of the trips or tail-pieces 16 or 17. The direct draft valvc 14 thus being open, the combustion increases, gradually raisin the temperature of the furnace, which causes the lever 20 to he llv f drawn inward by expansion of the lire-box so as to abut the arm I; of said tri-arm lever 34; thus rocking said lever and by engagerncnt of the arm (1- against lug 16 closing the directlll'ilfl.-()p(llillf; after which the combustion continues steadily under the indirect draft. This engagement of arm I) by lever 20 transpires before the lever 20 has moved inward. sutliciently to allow the ash-door 5 to close. The tri-arm lever 34 has preferably a central ball-scat fulcrum, as shown in Fig, allowing a universal movement, so that n'iovci'nont (if one arm will all'ect the two others, or it one arm be held stationary the device may be rocked on its seat with respect to the other two arms. Thus, when the iiredoor is closed, the arm (1 being caught, the device is practiraliy transformed to a twoarmcd lovcr (l f), with the arm I) in position for earlycngagcmcn t by lover 2(),'so that pressure against arm 6 will rock arm (1 against lug l6 and close the direct drattvalve. llowcvcr,should a simplc doublearm lover be employed, when the lever 20 so engaged arm I) it would not be possible to j opon the direct dral't valvc, ll tins should be desired while the l'urnacois in full blast. But by means of the trl-arm (l('\'] it u. in. dr-sirod to open the direct dral't-valvidurmp ,such operation, it is simply lwcossary lo upon the fire-door 4, thus releasing arm (2 "lhc device may thou he considered a. two-arm levcr (1 c, and the arm being released will allow the attendant to boar against ()H or both of the trip-lugs 16, 17, and thus opcn the direct draft-valve. The valve operating mechanism hcre described is desirable for its o'llicicncv and simplicity, but it will he un- 5 dcrstood that the direct-draft valve may be antomaticallyoperated from lever 20 through any suitable connections.

To summarize thc operation of the automatic governing meclninism, let us assume that the furnace set for freezing weather, or thirty degreesl ahrenhcit; that is the adjusting lever 28 is set at that point, so that the frame 23-25-26 is setto permit a certain expansion of the furnace before it affects the lever 20. Should the adjusting lever be set ill) for a higher temperature, as at fifty degrees, the connections-2623-25 would be shortened, causing the ex ansion of the firebox to act'sooner. Shou d it be set at a lower temperature, as at zero; said connections 262325 would be lengthened, causing the fire-box to expand still more against the back cross-piece 23 before drawing inward said lever 20.

Now, the" furnace being set for the desired temperature, say thirty degrees, the fire is started with the direct draft-valve 14 and ash-door 5 open, and with the check-door 6 of the lower smoke-box closed. After starting the fire, and when ready to leave the furnace, the attendantshould move inward the ash-door 5 till its finger or projection 30 engages the outwardly suspended lever 20, thus limiting the inwardmovement of the door and maintaining a proper opening-for the draft. As the temperature of the firebox rises, the force of'itsexpansion against the rear cross piece 23, by virtue of the con- .necting rods and 26, gradually draws the the necessary draft opening is left to main tain the desired furnace temperature. Any rise above thistemperature will be compensated for by the restriction of the.ash-door o ening, any decrease by enlargement t iereof, due to action of lever 20; so that the 4 desired temperature will be steadily maintained. Now should the operator have forgotten to move inward the ash-door, and gone away leaving it held open by the lug 32 engaging finger 33 onthe check-door 6, the resultant strong draft will produce a higher rate of combustion, raising the temperature and expanding the fire-box sufiicientlyto draw in the lever against the lug 31 on the check-doo'r, thus lifting the latter and checking draft from the fuel, while releasing the ash-door and allowing it to close. The furnace will then relax to its desired tempera ture, and allow the lever 20 to openthe ashdoor the slight amount necessary to maintain the same.

Should it be desired to maintain a low furnace temperature, as in mild weather, the frame .or connections 23, 25, 26 being properly shortened, the expansion, of the firebox will act immediately, draw the lever inward to close the ash-door and maintain the check-door slightly raised.

We make no claim herein to improvements in tee structure of the furnace per se, since the same forms the subject-matter of our onal appl'3at1on filed January 30, 1905, 'a-l No. 248 400-.

We claim as our invention and desire to secure byLetters Patent of the United States: 1. In a furnace or heater, the combination with a fire-box having an indirect draftpassage with its smoke-outlet at the-base of the front of the heater and having also a direct smoke-outlet at the upper front part of the heater, and a damper therefor, said fire-box havin a front" ash-door for controlling the supp y of air for combustion, a lever operating directly on said door for opening and closing it, mechanism controlled by the temperature of the fire-box for operating said lever, and means directly en gaged by said lever for operating said damper to close the upper direct smokoutlet after combustion has progressed,

a common smoke-pie in communication. with both smoke-out ets, and a check-valve for controlling the inlet of air to said pipe at the base of the heater, and said lever opera'ting directly upon and controlling said check-valve.

2. In combination with a fire-box having 7 an indirect draft-passage to and from its lower front and a direct draitassagethrough its upper front, and provide with a front ash-door, a check-valve controlling admission of air to said indirect draft-passage, and a damper controlling said direct draftpassage, of a'pendent lever at the front of said fire-box, means on said fire-box actuated by expansion thereof to move said lever inward or toward the fire-box, means aotuated by said lever for moving said damper to close said direct draft-passage when the lever first moves inward, connection between said lever and ash-door whereby the latter is cohtrolled by said lever, and means actuated by said lever for opening said check-valve when the lever continues its inward movement after the closing of said ash-door.

3. In a furnace, the combination of the fire-boxhavingat its front upper and lower smolre-boxes respectively adapted for connection with a smoke-pipe, there being an indirect draft-passageinto the lower smoke'-.

box and a direct draftassageintothe upper smoke-box, a damper 'or said latter passage,

an upright tiltinglever carrying said damper, said tilting lever having at its foot atailpiece projecting out through said smoke-box,

- a heat-controlled lever mounted at the front of the fire-box and actuated by rise of heat to move inward or toward the fire-box, an intermediately-fulcrumed lever having one arm engaging said tail-piece of the dampercarrying lever and whose other arm is adapted to be engaged by said heat-controlled lever when the latter is first moved inward, whereby said dainperis caused to close saiddirect draft-passage, an ash-door on thefront of the, fire-box having a finger engaging said heat controlled lever, whereby said ash-d0or,/ is

' controlled by the motion of said'lever', and

ii). i

i W, from the fire-box. ot a damper opening, a rocking lever carrying and provided with a tz'iihpieee for said said darn geYemng actuating trallv-fuie: med

tl u lever adaptei'l to engaged hy the fire-door when elesed, and second arm adapted to be en cilld governing lever when moved perature, and a third arm en the second arm is so engaged to bill said tail-pieee and thereby close said h aving' one vo i J innard and outward movements of i a .l'urnau r heater, the combination of uiirodpox' i (2 ring" a. front ash-door, asmolcepipe.eonnnuninatingr with the bottom of the fire-box below said asird or, a cheek-valve located below said arh loor for controlling, adniiission of air into smoke-pipe, a PSIILlQ-Di) lever mounted on the front 01' the heater adapted to more inward and outward and conneetml with the arsh-door for eon.- he name, Siliil' lever having its foot I said ('he ch-Valve for controlling the d means controlled hy eiipansion 1tion oi" the lire-hex [or operating re, the combination with th losing; ash-door, of

lever and 'heat-eontroliwl means re same, and a imam-med eenarm y adapted to move ini the ash-r hm oer end of ti satire tending:

pendent lever, heat-controller} means aetu' ating said lever to more imvardandoutward ac ording to riing' and lomarhn temperal ash-door having a linger overlying v. iereln the ash-door will move with the lz1"-.\'1i1 l and outward motions of the lover, a eheek-"raive adjacent to means whereby the ash-door ra n he held agar, by tliechw-li-valve when the latter is riosed, and means whereby said lever on moving inward a rertain distance wiil open the cheek-rake end thereby release the ash-door.

i .are the romhination with the in a in firebox having a Still-l rlruf ash-door, of a lendent lHYOi (tentto ash-door, a weight acting; on said lever to normally hold it outward l' om the tire-box, lwat-eontrolled means for moving said iOYCi' inward, said ash-door having a linger or projection over-- lying said lever, whereby said ash-door will l'ollov the inward motion of the lover, a smoke-pipe having direct and indirect eon 1- muniration with. the 'lire-hox respectively above and below said aslwioor, a direetdraft controlling damper d igned to he left open on starting eomhuation, and means whereby said lever rinses said damper on inward movementor" the iL'WOl" after eonihuslion has progressed l). in a inrnaee, he (-o1nlnn 'tion of a nendent lev r, a o'er; .t aetln u on the u i. i (7 hold the lower end outward, means aet rated by heat for moving the lever in mild, and a seif--elos ing ash-door haring; a finger-or projection overlvin tire lever and ada ited to follow it inward, a. SlI'lOlfiOv-llllt, and a hinged cheek-- door for admi in air to the ash-door having a ling (1' adapted to be engaged oy drawn inxvant in testimony whereof we allix our signatures, in presence of two \vitmisses.

IdlillOil J.

HENRY 

